The world holds very few unexplored places between zero and six feet off the ground. If humans can walk right up to it and take a picture, we probably already have. But the tops of the trees, like the bottom of the ocean, are a different story.
“We know so much less about arboreal mammal activity than we do about terrestrial mammal activity,” says Tremaine Gregory, a research scientist at the Smithsonian Conservation Biology Institute. She thought camera-trapping, a common method for obse